Ever since Thomas A. Watson (Alexander Graham Bell's assistant) patented the "polarized ringer" in 1878 and telephones obtained widespread use, unwanted telephone calls when one is sleeping have been a problem. Discourteous people call late at night and often wrong numbers disturb the sleeper at odd hours of the night.
People solved this problem by taking the phone off the hook, unplugging the phone from the wall, and lately disconnecting the modular jack at the back of the phone before they went to sleep. The problem with all these methods is that the phone has to be manually reconnected to place or receive calls. Often the phone would not be hung up, plugged in or otherwise reconnected and telephone calls during times when they are welcome are missed. In addition, people often forget to again disconnect their phones at night and are often rudely awakened by a midnight caller.
Business offices have their own problems with telephones. Unauthorized after hour use is of particular importance because it costs businesses thousands of dollars per year. Many attempts have been made to thwart unauthorized after hour business phone use. Among them are dial locks, and computerized line access codes. The problem with dial locks is they have to be installed each night and removed each morning. Also they can be easily defeated because they only protect the telephone itself and not the line. In addition they do not work with pushbutton phones. Computer access codes on the other hand require very expensive phone equipment which is beyond the means of most small firms.
What is needed is a device that will automatically turn all or some telephone functions on and off as a function of time. Many devices currently exist which will turn electric applicances operating on AC line current on and off at preprogrammed times. For example, patent number 4,588,901 describes a timer control for television to limit total viewing time to a preprogrammed limit by open circuiting the AC line when the programmed time expires. Many other ingenious timer controlled switches and circuits have been disclosed in previous patents and many others are currently for sale commercially. However, no device has been invented which solves the particular problems associated with telephone circuit timer control.